Abstract
Velocity calibration and estimation of microseismic event location are two important ingredients in microseismic monitoring. It is generally considered that the accurate estimation of microseismic event location depends on the accurate velocity structure. In this paper, very fast simulated annealing (VFSA) is first applied to invert velocity structure between the treatments well and the monitoring well by using perforation shot travel time data, and then is implemented to locate the microseismic events using the velocity structure obtained above. Unlike previous applications of VFSA using the objective function of misfit between the theoretical travel time and the observed travel time, we propose a novel objective function for VFSA which consists of the travel time differences of P-wave first arrivals between seismic traces. The P-wave first arrival travel time is calculated by means of a shooting ray tracing method. To illustrate the efficiency of the proposed method, a flat-layered model test is performed by considering the uncertainty of travel time picking. The numerical results indicate that the predicted microseismic event locations have a good match with the true values although the inverted velocity structure is not so accurate.
Highlights
Over the last ten years, the huge growth in unconventional reservoirs has caused a significant interest in microseismic fracture monitoring [1,2]
Various linear inversion techniques (e.g. least square and Singular value decomposition (SVD)) are performed to invert velocity structure and locate microseismic events by using first arrival travel times and particle motion of seismic P and/or S waves [3,4,6,7,8,9,10,11]. Those linear inversion methods strongly depend on the initial models that may lead to trap in local minimum [5] due to less receiver coverage (
To improve SA’s efficiency, Ingber [19] proposed a very fast simulated annealing (VFSA) method which has been used in solving various geophysical problems
Summary
Over the last ten years, the huge growth in unconventional reservoirs (e.g. shale gas, tight gas and tight oil) has caused a significant interest in microseismic fracture monitoring [1,2]. Various linear inversion techniques (e.g. least square and Singular value decomposition (SVD)) are performed to invert velocity structure and locate microseismic events by using first arrival travel times and particle motion of seismic P and/or S waves [3,4,6,7,8,9,10,11]. Pei et al applied VFSA to invert velocity structure through presenting a joint objective function of first arrival travel time misfits between the synthetic data and the observed data of both seismic P- and S-waves.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
